The pressures in diesel engine fuel systems can often be very high, and are often on the order of 10,000-30,000 PSI, compared with no more than about 60 PSI in a gasoline engine fuel system. The pressurized fuel exerts strong forces on many components of such systems, including the system seals in particular. For purposes of manufacturability, maintenance, expansion, etc., diesel fuel systems such as pumps and injector systems include openings that are sealed by plugs or partially sealed by valve guides.
In many cases, however, the plug or guide must seal again both a static surface and a dynamically loaded surface as the fuel pressure and system operations change. In such environments, the dynamic forces on one portion of the seal tend to pry up or “unzip” the static seal, leading to leakage and system failure. Although there have been attempts to solve this problem through increased tightening of seals and other traditional measures, leakage problems due to cycling-induced leakage continue to occur. While it is possible to increase the hardness of seals, this can lead to fracturing under pressure.
Although some implementations of the examples disclosed herein will operate to solve the noted problems, it will be appreciated that resolving such shortcomings is not a limitation or essential feature of the present innovation. This background discussion is presented for the reader's convenience, and is not intended to identify relevant prior art or to conclusively characterize any art. The teachings of the prior art will be best understood by reference to the prior art itself, and the foregoing discussion is not intended to extend the teachings of the prior art in any way. Any inconsistency in this characterization should be resolved in favor of actual prior art, not this background section.